These two authors contributed equally to this work. SUMMARYSalt stress from soil or irrigation water limits plant growth. A T-DNA insertion mutant in C24, named athspr (Arabidopsis thaliana heat shock protein-related), showed several phenotypes, including reduced organ size and enhanced sensitivity to environmental cues. The athspr mutant is severely impaired under salinity levels at which wild-type (WT) plants grow normally. AtHSPR encodes a nuclear-localized protein with ATPase activity, and its expression was enhanced by high salinity and abscisic acid (ABA). Overexpression (OE) of AtHSPR significantly enhanced tolerance to salt stress by increasing the activities of the antioxidant system and by maintaining K + /Na + homeostasis. Quantitative RT-PCR analyses showed that OE of AtHSPR increased the expression of ABA/stress-responsive, salt overly sensitive (SOS)-related and antioxidantrelated genes. In addition, ABA content was reduced in athspr plants with or without salt stress, and exogenous ABA restored WT-like salt tolerance to athspr plants. athspr exhibited increased leaf stomatal density and stomatal index, slower ABA-induced stomatal closure and reduced drought tolerance relative to the WT. AtHSPR OE enhanced drought tolerance by reducing leaf water loss and stomatal aperture. Transcript profiling in athspr showed a differential salt-stress response for genes involved in accumulation of reactive oxygen species (ROS), ABA signaling, cell death, stress response and photosynthesis. Taken together, our results suggested that AtHSPR is involved in salt tolerance in Arabidopsis through modulation of ROS levels, ABA-dependent stomatal closure, photosynthesis and K + /Na + homeostasis.

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In this study, PCR-denaturing gradient gel electrophoresis (DGGE) was applied to analyze the microbial communities in lake sediments from Lake Xuanwu, Lake Mochou in Nanjing and Lake Taihu in Wuxi. Sediment samples from seven locations in three lakes were collected and their genomic DNAs were extracted. The DNA yields of the sediments of Lake Xuanwu and Lake Mochou were high (10 mg/g), while that of sediments in Lake Taihu was relatively low. After DNA purification, the 16S rDNA genes (V3 to V5 region) were amplified and the amplified DNA fragments were separated by parallel DGGE. The DGGE profiles showed that there were five common bands in all the lake sediment samples indicating that there were similarities among the populations of microorganisms in all the lake sediments. The DGGE profiles of Lake Xuanwu and Lake Mochou were similar and about 20 types of microorganisms were identified in the sediment samples of both lakes. These results suggest that the sediment samples of these two city lakes (Xuanwu, Mochou) have similar microbial communities. However, the DGGE profiles of sediment samples in Lake Taihu were significantly different from these two lakes. Furthermore, the DGGE profiles of sediment samples in different locations in Lake Taihu were also different, suggesting that the microbial communities in Lake Taihu are more diversified than those in Lake Xuanwu and Lake Mochou. The differences in microbial diversity may be caused by the different environmental conditions, such as redox potential, pH, and the concentrations of organic matters. Seven major bands of 16S rDNA genes fragments from the DGGE profiles of sediment samples were further re-amplified and sequenced. The results of sequencing analysis indicate that five sequences shared 99%-100% homology with known sequences (Bacillus and Brevibacillus, uncultured bacteria), while the other two sequences shared 93%-96% homology with known sequences (Acinetobacter, and Bacillus). The study shows that the PCR-DGGE technique combined with sequence analysis is a feasible and efficient method for the determination of microbial communities in sediment samples.

BackgroundSexually transmitted infections (STIs) are some of the most common communicable conditions and exert impact on the health and lives of many hundreds of millions of people across the world every year. Screening high-risk populations and conducting comprehensive detection tests would lead to a significant improvement in preventing the transmission of STIs and help us to provide rapid treatment to those affected. Here, we successfully established and validated a novel high-throughput multiplex gene detection system (HMGS) for the simultaneous and semiquantitative detection of six important curable sexually transmitted pathogens in a single reaction from secretions samples.MethodFluorescently labeled primers were designed to target specific conserved and single-copy gene fragments of Ureaplasma urealyticum (U. urealyticum), Mycoplasma hominis (M. hominis), Chlamydia trachomatis (C. trachomatis), Neisseria gonorrhoeae (N. gonorrhoeae), Trichomonas vaginalis (T. vaginalis), and Treponema pallidum (T. pallidum). The specificity and sensitivity of the STI-HMGS was validated and optimized using plasmids and quantitative genomic DNA. Next, we validated the performances of the STI-HMGS for clinical application by testing samples of clinical secretions collected from patients who visited the gynecology and urology outpatient clinics of our reproductive medicine center. Results derived from the STI-HMGS were then compared with three approved commercialized kits that used to detect U. urealyticum, C. trachomatis and N. gonorrhoeae, respectively, followed by further validation with Sanger sequencing for all pathogens. Finally, a comprehensive analysis of epidemiology was performed among different subgroups to investigate the association between infection rates and clinically-relevant information.ResultsThe sensitivity of STI-HMGS for six target genes was 10 copies/µL. Data derived from the detection of 381 clinical secretions demonstrated that the STI-HMGS exhibited high concordance rate compared with approved commercialized kits and almost 100% sensitivity and specificity for the detection of six sexually transmitted pathogens when validated by Sanger sequencing. Semi-quantitative analysis found that STIs caused by N. gonorrhoeae had a significantly higher (P<0.05) pathogen load than the other pathogens. Infections caused by C. trachomatis were significantly more common in younger individuals (P<0.05). We also found that U. urealyticum infections were more likely to happen in females; while the males were more affected by N. gonorrhoeae (P<0.05).ConclusionsSTI-HMGS proved to be an efficient method for the semi-quantitative detection of six important curable sexually transmitted pathogens and therefore represents an alternative method for the clinical detection and monitoring of STIs.